Mutation screen reveals novel variants and expands the phenotypes associated with DYNC1H1

Area of Science:

• Genetics
• Neuroscience
• Molecular Biology

Background:

• The DYNC1H1 gene encodes a heavy chain subunit of cytoplasmic dynein, essential for intracellular cargo transport along microtubules.
• Dominant mutations in DYNC1H1 are linked to various neurological disorders, including spinal muscular atrophy with lower extremity dominance (SMA-LED) and Charcot-Marie-Tooth disease type 2O.

Purpose of the Study:

• To investigate the potential role of novel DYNC1H1 variants in motoneuron and related diseases.
• To expand the understanding of the phenotypic spectrum associated with DYNC1H1 mutations.

Main Methods:

• Analysis of a database comprising 1024 whole exome sequencing samples from patients with motoneuron and related diseases.
• Filtering for significant single nucleotide variations and subsequent segregation analysis in available family members.

Main Results:

• Identification of six novel, rare, and highly conserved DYNC1H1 variants.
• Three of these variants were determined to be likely pathogenic, associated with a broad range of phenotypes and distinct disease clusters.
• Evidence suggests DYNC1H1 variants can lead to both upper and lower motor neuron disease.

Conclusions:

• DYNC1H1 is implicated in a wider spectrum of motor neuron diseases than previously recognized, including upper motor neuron conditions.
• This study adds DYNC1H1 to the list of genes associated with spastic paraplegia and microtubule-dependent motor protein pathways.